The present invention relates generally to methods for adding a fuel to a gasoline-operated internal combustion engine and more particularly to a method for adding a gasoline fuel also containing a mixture of alcohol and water.
In the past, attempts have been made to add a mixture of alcohol and water (or water alone) to gasoline as part of the fuel for a gasoline-operated internal combustion engine. Typically, a liquid mixture of alcohol and water, or water alone, is stored in a container from which vapors of the mixture are withdrawn by bubbling through the container an external gas (e.g., air or exhaust gas from the internal combustion engine) or by creating a suction at the exit from the container, produced by a moving stream of exhaust gas. The mixture of water and alcohol vapors thus produced is relatively dilute, there being a relatively large volume of air or exhaust gas commingled with it, and some of the water and alcohol is in the form of small liquid droplets.
An example of a prior art method in which the water-alcohol mixture is withdrawn from its container as such vapors, by bubbling an external gas through the mixture, is shown in Alm et al., U.S. Pat. No. 3,749,376. An example of a prior art method in which the water-alcohol mixture is withdrawn from its container as such vapors due to a suction created by a stream of exhaust gas, with which the withdrawn water-alcohol mixture is then mixed is shown in von Brimer, U.S. Pat. No. 3,530,842. The vapors of water and alcohol thus formed by the prior art methods are used for cooling the internal combustion engine into which the alcohol-water mixture is introduced. Accordingly, in these prior art methods, it is important that these vapors consist, at least in part, of droplets of liquid which can be converted from liquid into gas to utilize the heat-absorbing characteristics of the conversion from the liquid to the gaseous state.
In Perry, U.S. Pat. No. 4,046,119, vapors of water alone are withdrawn from a container by bubbling air and exhaust gas through the container to provide a mixture of air, exhaust gas and water vapor which is then preheated before injection into the intake manifold of the engine.
In Colwell et al., U.S. Pat. No. 2,563,101, a liquid additive including water and alcohol, among other things, is mixed with gasoline and air at the intake manifold of an internal combustion engine.
A draw-back to withdrawing the water-alcohol mixture from its storage container as a vapor is that, in this condition, especially when the water-alcohol mixture is combined with an external gas, such as air or the engine's exhaust gas, it is difficult to meter or measure accurately a controlled amount of the water-alcohol mixture in relation to an amount of gasoline with which it is to be mixed. A disadvantage to introducing the alcohol-water mixture into the engine mixed with exhaust gas is that the latter will load down the engine with a gas volume which has already gone through the engine once and which, for the most part, has already been combusted.